Programmable or configurable impedance circuits are used in motor drives and other power conversion systems for a variety of purposes, including scaling and signal conditioning for feedback sensor signals such as input and/or output current sensors, intermediate DC link voltage sensors and the like. Power conversion product lines typically include multiple models having different voltage and/or current ratings. Thus, sensor signal levels may vary from one product to the next, requiring signal conditioning circuitry tailored for each individual product. However, providing specialized signal conditioning circuitry for each product is costly in terms of low component volume for each individual circuit board design and also in terms of the costs associated with maintaining inventory for a variety of different circuit board configurations. Configurable impedance circuits can be used in a given circuit board design, but programming these during manufacturing can be expensive in terms of personnel time and fixturing expense, particularly where a large number of programming signals must be applied to each board during manufacturing. Accordingly, there is a need for improved apparatus and techniques by which feedback signal conditioning and other programmable impedance circuits can be configured to accommodate use in a variety of different products and/or applications.